1. Field of the Invention
The present invention relates to an imaging apparatus including an impact absorbing mechanism.
2. Description of the Related Art
Conventional monitoring camera apparatuses have a dome cover covering a camera unit which is formed of polycarbonate resin having impact resistance, and an external casing covering a camera body which is formed of metal to provide impact resistance performance. Compared with the external casing formed of the metal, even if the dome cover formed of the resin is not destroyed by the impact, it may be instantaneously, largely deformed. Therefore, when the dome cover receives more than a certain amount of impact, the deformed dome cover may contact and damage an internal construction of the camera unit, and the internal construction may become nonfunctional.
To solve the issue described above, for example, Japanese Patent Application Laid-Open No. 2003-174572 discusses a monitoring camera apparatus including an impact absorbing mechanism. With reference to FIG. 11, the conventional monitoring camera including the impact absorbing mechanism will be described. A rotating base 301 which is a supporting member for supporting a camera unit 300 is fixed to a supporting post of a rotation bracket 302 with an axis screw 304 through an elongated hole 302a provided in a vertical direction of the supporting post. A coil spring 303 is provided between the axis screw 304 and the supporting post. With this arrangement, the rotating base 301 is supported to be rotatable in a tilt direction and to be linearly movable in a vertical direction. Thus, the impact force hitting a cover 305 can be absorbed, and the camera unit 300 can be protected from the damage.
According to the conventional monitoring camera apparatus including the impact absorbing mechanism, since the camera unit 300 can linearly move in the vertical direction, against the impact from the vertical direction of the dome cover, the camera unit 300 can retreat and absorb the impact. However, against the impact from an oblique direction of the dome cover, the camera unit 300 cannot always perform a retreat operation and thus may have been damaged by the impact. The monitoring camera apparatus is often mounted onto a ceiling or a wall surface, and it is necessary to assume that the intentional impact force may be applied from any direction of the dome cover. Thus, it has been an issue that the conventional construction of the monitoring camera apparatus is insufficient.
A clearance between the dome cover and the internal construction of the monitoring camera apparatus becomes smallest between the dome cover and a lens unit. When an intentional impact is applied to the dome cover, a force from the dome cover deformed by the impact is transmitted most to the lens unit. Particularly, most of the force from the dome cover deformed by the impact will be a pressing force onto the lens unit in an optical axis direction. However, the conventional monitoring camera apparatus including the impact absorbing mechanism cannot always perform the retreat operation in the optical axis direction depending on a tilt angle of the camera unit 300.